Skin Tone:  Warmer skin tones often pair well with golden or auburn hues, which add warmth and vibrancy to the face. Cooler skin tones complement ash or cool brown shades, creating a more sophisticated and balanced look. Remember, this applies to eyebrow tinting as well! 

Hair Type:  Fine hair can handle lighter shades beautifully, as it won't appear weighed down. Coarse hair can take on darker tones without looking too heavy, and it can even help add texture and volume.  

Natural Hair Color: Consider your starting point as this will affect how the color takes. Lighter hair will take on the color easier and achieve brighter results, while darker hair might require bleaching beforehand to achieve lighter shades. Bleaching can be a more complex process, so if you're unsure, opt for a shade a few tones darker than your natural color for a more foolproof result.